With increasing of mobile Internet services, data amount in a wireless communication network surges, which accelerates demands for bandwidths. In order to alleviate congestion of a mobile cellular network, a network operator needs to deploy more base stations to improve network capacity, which inevitably results in increasing of investment cost and maintenance cost. In order to solve the conflict, increasingly more network operators select a mobile data distribution manner, where a part of data in the mobile network is distributed to other available access technologies, so as to be used as compensation of the mobile network. Recently, the most important compensation network technologies used for the mobile data distribution include WiFi (Wireless Fidelity, wireless fidelity), a home base station and so on.
The WiFi, being a standard of a WLAN (Wireless Local Access Network, wireless local access network), is a communication network composed of a wireless network card and an AP (Access Point, access point). The AP is generally called a network bridge or an access point, connecting a wired local access network and the wireless local access network; a user equipment with a wireless network card may share resources of the wired local access network or even a wide area network through the AP, where a working principle of the AP is equivalent to a HUB (hub) or a router with a built-in radio transmitter; and the wireless network card is located in the user equipment and is responsible for receiving a signal transmitted by the AP.
LTE (Long Term Evolved, long term evolved network) is a mobile communication network actively researched by every manufacturer in the 3GPP (3rd Generation Partnership Program, 3rd generation partnership program) organization, and is an evolved network of a UMTS (Universal Mobile Telecommunication System, universal mobile telecommunication system). The objective of LTE is to provide a low-cost network capable of reducing time delay, increasing a user data rate, and increasing system capacity and coverage. An air interface of the LTE network is implemented by deploying the base station, and the UE (User Equipment, user equipment) communicates with the base station, so as to implement air interface transmission of the mobile service.
In the LTE technology, the data transmitted at the air interface is borne on different RBs (Radio Bearer, radio bearer) according to QoS (Quality of Service, Quality of Service) and other information, where an SRB (Signaling Radio Bearer, signaling radio bearer) is used to bear an RRC (Radio Resource Control, radio link control) message, that is: RRC signaling; and a DRB (Data Radio Bearer, data radio bearer) is used to bear data. During and/or after a process that the base station establishes the RRC with the UE, the base station may configure one or more RBs for the UE, for bearing different types of data.
In the existing 3GPP standard, the solution of supporting the WLAN to perform the distribution for the UMTS or LTE network is mainly performed in an EPS (Evolved Packet System, evolved packet system) of a core network. Through configuration, different traffic flows are distributed to the wireless air interface of the UMTS/LTE or the WLAN in the network for transmission. A distribution point of the solution is at the core network side.
In addition, a distribution point of another distribution solution is at an access network side of the LTE or UMTS, for example, a base station of the LTE, or an RNC (Radio Network Controller, wireless network controller) of the UMTS. As compared with the distribution performed at the core network side, the WiFi distribution performed at the access network side has an advantage that: the access network side is closer to air interface transmission, so as to acquire state information of the air interface transmission in real time, so that distribution scheduling may be adjusted in real time according to the state of the air interface transmission, thereby acquiring better data transmission efficiency. Taking the WiFi distribution performed in the base station of the LTE as an example, the solution of performing the WiFi distribution in the base station is distribution based on an IP layer, that is, IP packet data of a user plane from an S1 interface is distributed to an access layer of the LTE and an access layer of the WiFi through a distribution scheduling policy, so as to perform air interface transmission through a Uu interface of the LTE and an 802.11 interface of the WiFi. In addition to the IP layer distribution solution, the distribution may be performed in a PDCP (Packet Data Convergence Protocol, packet data convergence protocol) layer, an RLC (Radio Link Control, radio link control) layer, and a MAC (Medium Access Control, medium access control) layer. In the distribution solutions, distribution points are put under the LTE PDCP layer, the RLC layer, and the MAC layer for performing the distribution.
In addition to layer difference of the distribution points, according to the distribution policy, the WiFi distribution may be classified into distribution performed according to packets and distribution performed according to bearers. In the distribution performed according to packets, all the bearer data transmitted by the core network through the S1 interface is distributed to the air interface side of the LTE and the WiFi according to the distribution scheduling policy; and in the distribution performed according to bearers, according to the configuration, some bearers are distributed to the air interface of the LTE side for transmission, and the other bearers are distributed to the air interface of the WiFi side for transmission, and before the configuration is not changed, distribution directions of the bearers are determined.
During the implementation process of the present invention, the inventor finds that in the LTE technology, when an RLF (Radio Link Failure, radio link failure) is detected, the UE may initiate an RRC (Radio Resource Control, radio resource control) connection re-establishing process. Generally, there are three conditions for determining that the RLF occurs:
(1) A physical link problem: when successively receiving N310 “out-of-sync (out-of-sync)” indications from the physical layer, the RRC layer of the UE starts a T310 timer; after the T310 timer expires, the RRC layer of the UE determines that the RLF occurs. Before the T310 expires, when successively receiving N311 “in-sync (in-sync)” indications from the physical layer, the RRC layer of the UE stops the T310 timer, so as to restore the link.
(2) After receiving a random access problem indication sent by a MAC (Media Access Control, medium access control) layer, the RRC of the UE determines that the RLF occurs.
(3) After the RRC layer of the UE receives an indication that re-transmission reaches the maximum number of times sent by an RLC (Radio Link Control, radio link control) layer, the UE determines that the RLF occurs.
Recently, the industry only has an accessing solution when the RLF occurs at the LTE side, but does not provide an accessing solution when the RLF occurs at the WiFi side.